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Mirena Side Effects

While Mirena is considered one of the most effective and safe forms of birth control available, it can carry some risks that, in rare cases, may be dangerous to the patient’s future fertility and possibly her life.

*Please seek the advice of a medical professional before discontinuing the use of this medical device.

Most women use Mirena with few, if any side problems. However, the intrauterine device has been linked to a range of side effects ranging from the minor, such as temporary discomfort or spotting to the serious, but rare, possibility of potentially fatal conditions, such as ectopic pregnancy, certain infections and intracranial hypertension.

Some women report extreme pain during insertion of the Mirena and for several days after, while others experience relatively minor discomfort or cramping. Spotting, dizziness and bleeding, as well as inflammation of the vulva and vagina are also common side effects. Some women experience a depressed or altered mood.

mirena IUD resting on a hand
The Mirena IUD is small enough to fit in the palm of a hand

Periods may become shorter and lighter and may even stop after a few months or a year. Bayer says about 20 percent of women stop having periods after a year. This is because the levonorgestrel in Mirena reduces the monthly thickening of the uterus lining. Periods will resume after Mirena is removed.

The manufacturer recommends notifying a doctor if bleeding remains heavier than usual or if it increases after it has been light for a while.

Patients are advised to tell their doctors if their symptoms don’t stop 30 minutes after Mirena insertion so the doctor can determine if the placement needs to be adjusted.

Bayer says ovarian cysts may occur but usually disappear.

About 12 percent of women with Mirena will develop a cyst on the ovary. If the cyst causes pain, it may require surgery.

Other potential side effects include abdominal pain, back pain, nervousness, nausea, vomiting, bloating, breast pain or tenderness, changes in hair growth, acne, reduced libido, itching or rash and puffiness in the hands, feet, ankles or face.

Can Your IUD Fall Out?

It is also possible for the device to come out of the uterus or pushed out of its proper location. If that happens, women should use back-up birth control and call their healthcare providers. This happens in something between 2 percent and 10 percent of women in the first year after insertion. It is more likely in women who haven’t been pregnant, are younger than 20 years old, have a history of very heavy or painful periods, or had their Mirena inserted right after giving birth or a second trimester abortion.

Expulsions

One gynecologist told Self magazine she had seen about three expulsions happen in her 15 years of practice.

Expulsion, or partial expulsion may happen if the IUD wasn’t inserted in the right position, possibly too low in the uterus.

Symptoms of IUD expulsion include:

  • Bleeding
  • Pain
  • Heavier menstrual flow
  • Cramping
  • Seeing the Mirena outside your body.

The chance of a second IUD being expelled may be higher, as high as 20 or 30 percent, and it may be advisable to ask the doctor in this case about using an ultrasound to ensure proper placement.

Weight gain is also a potential side effect. Less than 5 percent of women in clinical studies gained weight while they had Mirena. The average weight gain was found by researchers to be 4.4 pounds at 6 or 12 months.

The device can be removed at any time a patient would like to become pregnant. Bayer says 8 out of 10 women who have Mirena removed succeed in becoming pregnant within a year.

Can You Still Get Pregnant With Mirena?

Although the contraception effectiveness rate of Mirena is greater than 99 percent, it is possible to the device will fail to prevent pregnancy. If a woman becomes pregnant while using Mirena, the doctor should remove the device because leaving it in place may increase the risk of spontaneous abortion, preterm labor and possibly even the death of the woman.

Some symptoms of pregnancy include:

  • Nausea
  • Fatigue
  • Breast tenderness

Pregnancy with Mirena also carries a risk of severe infection. Removing or manipulating the Mirena may also result in loss of pregnancy. With Mirena, there is an increased risk of any pregnancy being ectopic, which is a dangerous condition that can lead to a loss of fertility and in some cases, can be fatal. Among the signs of an ectopic pregnancy are unusual bleeding or abdominal pain. Ectopic pregnancy is an emergency that requires immediate medical attention and often surgery.

If you think you may be pregnant, notify the doctor and arrange to have a blood test, which will detect a pregnancy earlier than a home pregnancy test.

Can Mirena Cause Infections?

Some women who use intrauterine devices develop pelvic inflammatory disease (PID), a serious pelvic infection, which is usually sexually transmitted. This side effect is usually limited to the first three weeks after the IUD is inserted. The risk of developing PID from an IUD is about 1 in 100. Other risk factors for PID including having an untreated sexually transmitted disease, having more than one sex partner, having a sex partner who has other sex partners, having a previous PID and being sexually active and younger than 25. Douching can also be a risk factor.

PID can lead to infertility, ectopic pregnancy or ongoing pelvic pain. It is often treated with antibiotics, but may require surgery and even a hysterectomy. In rare cases, it can cause death.

Symptoms of PID include:

  • Abdominal pain
  • Fever
  • An unusual discharge, or bad odor
  • Pain or bleeding during sex
  • Burning feeling during urination
  • Bleeding between periods

Diagnosed early, pelvic inflammatory disease can be treated with antibiotics. Any damage done by the disease to the body before treatment cannot be reversed, so early treatment is important. Untreated PID can lead to complications including scar tissue in and on the fallopian tubes, ectopic pregnancy, infertility and long-term pelvic pain.

Another rare, but potentially fatal side effect may develop in the first few days after a woman gets a Mirena. This is a dangerous infection called sepsis. Symptoms include severe pain or unexplained fever. If these develop, the patient should call her doctor immediately.

Can Mirena Cause Organ Perforation?

Mirena also may attach to or perforate the wall of the uterus and cause other problems. The risk of Mirena becoming attached to perforating the wall of the uterus is increased if Mirena is inserted while the patient is breastfeeding. One study showed the risk of perforation for women who are lactating was 6.3 for every 1,000 insertions, compared to 1 for every 1,000 insertions in women who are not lactating.

Most often, when perforation occurs, it happens during insertion, but may not be noticed until later.

Symptoms of perforation may include:

  • Severe, cramp-like pain that lasts for weeks
  • Pain with intercourse
  • Pain or blood when going to the bathroom (rare)
  • Spotting

If Mirena perforates the uterus, it may no longer be effective at preventing pregnancy. It may travel outside the uterus and scar a woman internally. It may also cause infection or damage other organs. Surgical removal may be required. In that case, in order to find the Mirena, radiologists may use ultrasound or x-ray. If the doctor has trouble finding and removing the Mirena, more than one surgery may be needed.

Is There a Risk of Intracranial Hypertension With Mirena?

Some women say they have suffered from a condition called intracranial hypertension or pseudotumor celebri, which is an unexplained increase of pressure inside the head. The symptoms of the condition mimic a brain tumor.

Intracranial Hypertension illustration
Illustration showing Intracranial Hypertension

Symptoms of intracranial hypertension may include:

  • Severe headache
  • Visual changes
  • A whooshing noise in the ears
  • Pain in the arms, legs and back
  • Neck stiffness
  • Dizziness
  • Nausea and vomiting

It may cause swelling of the optic nerve and possibly vision loss. It may also be fatal.

Researchers who examined data from the Adverse Events Reporting System run by the Food and Drug Administration found a higher than expected number of reports of intracranial hypertension.

Treatments for the condition can involve various drugs, including drugs known as carbonic anhydrase inhibitors. When medication is not successful and vision is in danger, a type of surgery called optic nerve fenestration may be performed.

A doctor may also recommend an operation to implant a neurological shunt to prevent vision loss and treat headaches.


Elaine Silvestrini is a career journalist with a strong desire to learn, explain, and help people. While working at Drugwatch, Elaine has reported on breaking news involving prescription drugs and medical devices and has written pieces on several large pharmaceutical companies and other topics. She is dedicated to telling people what they need to know about developments in the news, and helping consumers understand what they can do when something goes wrong with their drugs and medical devices.

Hide Sources

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